docs: def defined_at():
      """
      Get definition location of a pattern or a match (outside of rebulk package).
      :return:
      :rtype:
      """
      if DEBUG:
          frame = inspect.currentframe()
          while frame:
              try:
                  if frame.f_globals['__package__'] != __package__:
                      break
              except KeyError:  # pragma:no cover
                  # If package is missing, consider we are in. Workaround for python 3.3.
                  break
              frame = frame.f_back
          ret = Frame(frame.f_lineno,
                      frame.f_globals.get('__package__'),
                      frame.f_globals.get('__name__'),
                      frame.f_code.co_filename)
          del frame
          return ret